After finishing my education here next year(same year I turn 21), I'm planning on renouncing my Singapore citizenship and move to Japan amd go on to study at their University.

Now what's worrying me is whether Singapore will stop me because I haven't go for National Service even though I have no plans on staying here anymore. I'm eligible for National Service and have deferred once before.

Now the questions are..

1. Whats the demerit of renouncing Singapore's citizenship?

2. Am I allowed to renounce without going NS?

3. Will I still be considered a deserter even after renouncing citizenship?

After finishing my education here next year(same year I turn 21), I'm planning on renouncing my Singapore citizenship and move to Japan amd go on to study at their University.

Now what's worrying me is whether Singapore will stop me because I haven't go for National Service even though I have no plans on staying here anymore. I'm eligible for National Service and have deferred once before.

Now the questions are..

1. Whats the demerit of renouncing Singapore's citizenship?

First of all you cannot renounce your citizenship unless you have fulfilled your National Service obligation.

2. Am I allowed to renounce without going NS?

NO.

3. Will I still be considered a deserter even after renouncing citizenship?

As you are not allowed to renounce before doing NS, and holding citizenship in two countries past the age of 21, you are breaking two laws, not just one. It's illegal to hold two different citizenships after the age of majority (in Singapore) and if you leave the country (assuming you are allowed to leave) once your deferment has expired you will also be considered a deserter. If that happens, If you are somehow recognized coming through the airport you can be picked up and jailed. So for all practical purposes, you will never be allowed to enter Singapore again. Ever.

Additionally, if you have already had a deferment you can bet your bottom dollar they already have your details flagged if you were a naturalized Citizen or if one parent was a non-citizen on your Birth Certificate.

As you are no doubt aware, few people outside Japan speak Japanese fluently, of those that do many appear more fluent than
they really are. When it comes to reading and writing Japanese then the number are even fewer (even worse the foreigners that live there and never even bother to learn hiragana). Therefore extremely few on this board will understand your posts. This what Jpatokal meant when he suggested using the Japanese site.